1 | /*!
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2 | * negotiator
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3 | * Copyright(c) 2012 Federico Romero
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4 | * Copyright(c) 2012-2014 Isaac Z. Schlueter
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5 | * Copyright(c) 2015 Douglas Christopher Wilson
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6 | * MIT Licensed
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7 | */
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8 |
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9 | 'use strict';
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10 |
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11 | /**
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12 | * Cached loaded submodules.
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13 | * @private
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14 | */
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15 |
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16 | var modules = Object.create(null);
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17 |
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18 | /**
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19 | * Module exports.
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20 | * @public
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21 | */
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22 |
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23 | module.exports = Negotiator;
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24 | module.exports.Negotiator = Negotiator;
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25 |
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26 | /**
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27 | * Create a Negotiator instance from a request.
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28 | * @param {object} request
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29 | * @public
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30 | */
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31 |
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32 | function Negotiator(request) {
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33 | if (!(this instanceof Negotiator)) {
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34 | return new Negotiator(request);
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35 | }
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36 |
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37 | this.request = request;
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38 | }
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39 |
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40 | Negotiator.prototype.charset = function charset(available) {
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41 | var set = this.charsets(available);
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42 | return set && set[0];
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43 | };
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44 |
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45 | Negotiator.prototype.charsets = function charsets(available) {
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46 | var preferredCharsets = loadModule('charset').preferredCharsets;
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47 | return preferredCharsets(this.request.headers['accept-charset'], available);
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48 | };
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49 |
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50 | Negotiator.prototype.encoding = function encoding(available) {
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51 | var set = this.encodings(available);
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52 | return set && set[0];
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53 | };
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54 |
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55 | Negotiator.prototype.encodings = function encodings(available) {
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56 | var preferredEncodings = loadModule('encoding').preferredEncodings;
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57 | return preferredEncodings(this.request.headers['accept-encoding'], available);
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58 | };
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59 |
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60 | Negotiator.prototype.language = function language(available) {
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61 | var set = this.languages(available);
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62 | return set && set[0];
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63 | };
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64 |
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65 | Negotiator.prototype.languages = function languages(available) {
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66 | var preferredLanguages = loadModule('language').preferredLanguages;
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67 | return preferredLanguages(this.request.headers['accept-language'], available);
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68 | };
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69 |
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70 | Negotiator.prototype.mediaType = function mediaType(available) {
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71 | var set = this.mediaTypes(available);
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72 | return set && set[0];
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73 | };
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74 |
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75 | Negotiator.prototype.mediaTypes = function mediaTypes(available) {
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76 | var preferredMediaTypes = loadModule('mediaType').preferredMediaTypes;
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77 | return preferredMediaTypes(this.request.headers.accept, available);
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78 | };
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79 |
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80 | // Backwards compatibility
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81 | Negotiator.prototype.preferredCharset = Negotiator.prototype.charset;
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82 | Negotiator.prototype.preferredCharsets = Negotiator.prototype.charsets;
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83 | Negotiator.prototype.preferredEncoding = Negotiator.prototype.encoding;
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84 | Negotiator.prototype.preferredEncodings = Negotiator.prototype.encodings;
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85 | Negotiator.prototype.preferredLanguage = Negotiator.prototype.language;
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86 | Negotiator.prototype.preferredLanguages = Negotiator.prototype.languages;
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87 | Negotiator.prototype.preferredMediaType = Negotiator.prototype.mediaType;
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88 | Negotiator.prototype.preferredMediaTypes = Negotiator.prototype.mediaTypes;
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89 |
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90 | /**
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91 | * Load the given module.
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92 | * @private
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93 | */
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94 |
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95 | function loadModule(moduleName) {
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96 | var module = modules[moduleName];
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97 |
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98 | if (module !== undefined) {
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99 | return module;
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100 | }
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101 |
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102 | // This uses a switch for static require analysis
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103 | switch (moduleName) {
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104 | case 'charset':
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105 | module = require('./lib/charset');
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106 | break;
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107 | case 'encoding':
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108 | module = require('./lib/encoding');
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109 | break;
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110 | case 'language':
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111 | module = require('./lib/language');
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112 | break;
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113 | case 'mediaType':
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114 | module = require('./lib/mediaType');
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115 | break;
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116 | default:
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117 | throw new Error('Cannot find module \'' + moduleName + '\'');
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118 | }
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119 |
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120 | // Store to prevent invoking require()
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121 | modules[moduleName] = module;
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122 |
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123 | return module;
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124 | }
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